NUMERICAL SIMULATION ON STEADY-STATE FOR HEAT AND MASS TRANSFER IN AN UNSATURATED POROUS BED

摘要

Based on the volume-averaging method, in the present paper, a general mathematical model with cylindrical coordinate system is developed with some considerations of introducing more transport mechanisms, for example, water evaporation and condensation in the moisture porous soil, relative motions between water-liquid phase and gas-mixture phase, effect of soil bed wall on transport process etc. To conduct numerical calculations, basic ambient parameters are chosen as: ambient temperature Ta=30℃, relative humidity RH=60%, radiant heat flux I=300W/m~2 and wind speed Va=1m/s. The calculating domain of cylindrical bed is fixed as: bed height H=0.15m and bed radius R=0.15m. Various field distributions are simulated by pressure-based algorithm with treating staggered grid in primitive variables and ADI technique for solving coupled linear equations.